BALTIMORE -- It may not have been the Rangers’ strong suit during the regular season, but in Game 1 of the American League Division Series, the bullpen became their secret weapon.

Texas wasn’t expecting left-handed starter Andrew Heaney to offer the club more than three or four innings on Saturday; he tossed 3 1/3 frames of one-run ball before giving way to the relief corps.

Dane Dunning, Will Smith, Josh Sborz, Aroldis Chapman and José Leclerc then combined to twirl 5 1/3 innings of one-run ball and hold off the No. 1 seed Orioles, earning the Rangers a 3-2 win and sending the sellout crowd of 46,450 fans at Camden Yards home unhappy.

Make no mistake, though. It wasn’t a breezy afternoon for the quintet.

“It started with Andrew. He hadn’t pitched in a while, and he got us where we were hoping he would get us,” said Rangers manager Bruce Bochy. “He did a nice job and set it up nicely for Dunning, who did a good job to bridge it to our [setup] guys. It worked out well. The bullpen did a great job.

“Got bumpy, but [they] found a way to get through it.”

That was no more apparent than in Chapman’s eighth inning, as the longtime closer walked the first two batters he faced on nine pitches. Anthony Santander, who had answered Josh Jung’s sixth-inning solo homer with one of his own in the bottom half of the frame, was due up next, and with Bochy unable to go to another reliever due to the three-batter minimum, it was up to Chapman.

The 35-year-old southpaw answered the bell by inducing a double-play ball to Jung at third base, which he said was “the key.” Chapman then struck out Ryan Mountcastle with a 101.4 mph sinker up and away to escape the jam.

“Lost a little bit of control at the time, and [I] just came back and tried to focus in on throwing strikes,” Chapman said through an interpreter. “Feel really good about the outcome.”

It took that type of high-wire act for most of the Rangers’ relievers to keep the Orioles -- a team with an offense that rivals theirs as one of the best in the Majors -- at bay. And, in some cases, they got some help along the way.

Leclerc was the biggest beneficiary in the ninth inning. Leadoff batter Gunnar Henderson hit a single, but when he then attempted to steal second base to get into scoring position in a one-run game, he was thrown out by Rangers backstop Jonah Heim in a sequence O’s manager Brandon Hyde called a “miscommunication.”

“That was the best play of my life,” Leclerc said. “I feel that was the key for me because I got more confidence, and then I could just go and try to get the next guy out.”

Before them, Dunning gave up only Santander’s solo shot in his two frames, helped out by Smith’s strikeout of Henderson to end the sixth, and Sborz punched out two in his one inning, the only straightforward outing among the bunch.

It was the bullpen’s first run allowed this postseason after they kept the Rays off the board in their Wild Card Series sweep.

“It was big,” Sborz said. “Now we have the leverage to use our guys when we want to, almost. I think the way we pitched in Tampa, we set the tone there. … We’re just kind of feeding off each other and trying to get outs. And if you don’t get all three, someone else can come pick you up. That’s kind of the mentality we’ve had.”

For a unit that ranked 24th in MLB this season with a 4.77 ERA, that’s no small feat. But the Rangers have faith that this postseason can continue to be a different story for them.

If it is, Texas’ chances of making a deep postseason run will only grow stronger.

“Nobody in here is doubting it. Nobody doubts what those guys can do,” Heaney said. “We don’t care about anything other than what’s in front of us, and those guys go out there and they’re going to do their best and pitch their [butts] off to get people out.

“They deserve a lot of credit for the way they’ve been closing out games here recently.”